There have been lots of Xaviers in the Nady family, but only one has ever hit a home run off a big-league pitcher. In fact, Xavier Nady of the Mets was the first person with the initial "X" to ever hit a homer in the majors—on April 2, 2003, off San Francisco's Damian Moss.
He's also the first of the Xaviers in his paternal line to change the pronunciation so he can have a cool nickname.
Xavier Clifford Nady, or Xavier VI, said he did not know much about his early ancestry, other than he pronounces his first name differently, putting a modern-day signature on a 16th-century name. Nady's father pronounces it ZAY-vee-yer — "That's the correct way," Nady said. But Nady, whose Mets teammates call him X or X-Man, prefers EX-ay-vee-yer to, ahem, exaggerate the X.
"Why not, right?" Nady said. "It's pretty cool." [Link]